#!/usr/bin/env python3
"""Post or update a PR comment with memory impact analysis results.

This script creates or updates a GitHub PR comment with memory usage changes.
It uses the GitHub CLI (gh) to manage comments and maintains a single comment
that gets updated on subsequent runs.
"""

from __future__ import annotations

import argparse
import json
from pathlib import Path
import subprocess
import sys

# Add esphome to path for analyze_memory import
sys.path.insert(0, str(Path(__file__).parent.parent))

# pylint: disable=wrong-import-position

# Comment marker to identify our memory impact comments
COMMENT_MARKER = "<!-- esphome-memory-impact-analysis -->"


def load_analysis_json(json_path: str) -> dict | None:
    """Load memory analysis results from JSON file.

    Args:
        json_path: Path to analysis JSON file

    Returns:
        Dictionary with analysis results or None if file doesn't exist/can't be loaded
    """
    json_file = Path(json_path)
    if not json_file.exists():
        print(f"Analysis JSON not found: {json_path}", file=sys.stderr)
        return None

    try:
        with open(json_file, encoding="utf-8") as f:
            return json.load(f)
    except (json.JSONDecodeError, OSError) as e:
        print(f"Failed to load analysis JSON: {e}", file=sys.stderr)
        return None


def format_bytes(bytes_value: int) -> str:
    """Format bytes value with comma separators.

    Args:
        bytes_value: Number of bytes

    Returns:
        Formatted string with comma separators (e.g., "1,234 bytes")
    """
    return f"{bytes_value:,} bytes"


def format_change(before: int, after: int) -> str:
    """Format memory change with delta and percentage.

    Args:
        before: Memory usage before change (in bytes)
        after: Memory usage after change (in bytes)

    Returns:
        Formatted string with delta and percentage
    """
    delta = after - before
    percentage = 0.0 if before == 0 else (delta / before) * 100

    # Format delta with sign and always show in bytes for precision
    if delta > 0:
        delta_str = f"+{delta:,} bytes"
        # Use 🚨 for significant increases (>1%), 🔸 for smaller ones
        emoji = "🚨" if abs(percentage) > 1.0 else "🔸"
    elif delta < 0:
        delta_str = f"{delta:,} bytes"
        # Use 🎉 for significant reductions (>1%), ✅ for smaller ones
        emoji = "🎉" if abs(percentage) > 1.0 else "✅"
    else:
        delta_str = "+0 bytes"
        emoji = "➡️"

    # Format percentage with sign
    if percentage > 0:
        pct_str = f"+{percentage:.2f}%"
    elif percentage < 0:
        pct_str = f"{percentage:.2f}%"
    else:
        pct_str = "0.00%"

    return f"{emoji} {delta_str} ({pct_str})"


def format_symbol_for_display(symbol: str) -> str:
    """Format a symbol name for display in markdown table.

    Args:
        symbol: Symbol name to format

    Returns:
        Formatted symbol with backticks or HTML details tag for long names
    """
    if len(symbol) <= 100:
        return f"`{symbol}`"
    # Use HTML details for very long symbols (no backticks inside HTML)
    return f"<details><summary><code>{symbol[:97]}...</code></summary><code>{symbol}</code></details>"


def create_symbol_changes_table(
    target_symbols: dict | None, pr_symbols: dict | None
) -> str:
    """Create a markdown table showing symbols that changed size.

    Args:
        target_symbols: Symbol name to size mapping for target branch
        pr_symbols: Symbol name to size mapping for PR branch

    Returns:
        Formatted markdown table
    """
    if not target_symbols or not pr_symbols:
        return ""

    # Find all symbols that exist in both branches or only in one
    all_symbols = set(target_symbols.keys()) | set(pr_symbols.keys())

    # Track changes
    changed_symbols = []
    new_symbols = []
    removed_symbols = []

    for symbol in all_symbols:
        target_size = target_symbols.get(symbol, 0)
        pr_size = pr_symbols.get(symbol, 0)

        if target_size == 0 and pr_size > 0:
            # New symbol
            new_symbols.append((symbol, pr_size))
        elif target_size > 0 and pr_size == 0:
            # Removed symbol
            removed_symbols.append((symbol, target_size))
        elif target_size != pr_size:
            # Changed symbol
            delta = pr_size - target_size
            changed_symbols.append((symbol, target_size, pr_size, delta))

    if not changed_symbols and not new_symbols and not removed_symbols:
        return ""

    lines = [
        "",
        "<details>",
        "<summary>🔍 Symbol-Level Changes (click to expand)</summary>",
        "",
    ]

    # Show changed symbols (sorted by absolute delta)
    if changed_symbols:
        changed_symbols.sort(key=lambda x: abs(x[3]), reverse=True)
        lines.extend(
            [
                "### Changed Symbols",
                "",
                "| Symbol | Target Size | PR Size | Change |",
                "|--------|-------------|---------|--------|",
            ]
        )

        # Show top 30 changes
        for symbol, target_size, pr_size, delta in changed_symbols[:30]:
            target_str = format_bytes(target_size)
            pr_str = format_bytes(pr_size)
            change_str = format_change(target_size, pr_size)
            display_symbol = format_symbol_for_display(symbol)
            lines.append(
                f"| {display_symbol} | {target_str} | {pr_str} | {change_str} |"
            )

        if len(changed_symbols) > 30:
            lines.append(
                f"| ... | ... | ... | *({len(changed_symbols) - 30} more changed symbols not shown)* |"
            )
        lines.append("")

    # Show new symbols
    if new_symbols:
        new_symbols.sort(key=lambda x: x[1], reverse=True)
        lines.extend(
            [
                "### New Symbols (top 15)",
                "",
                "| Symbol | Size |",
                "|--------|------|",
            ]
        )

        for symbol, size in new_symbols[:15]:
            display_symbol = format_symbol_for_display(symbol)
            lines.append(f"| {display_symbol} | {format_bytes(size)} |")

        if len(new_symbols) > 15:
            total_new_size = sum(s[1] for s in new_symbols)
            lines.append(
                f"| *{len(new_symbols) - 15} more new symbols...* | *Total: {format_bytes(total_new_size)}* |"
            )
        lines.append("")

    # Show removed symbols
    if removed_symbols:
        removed_symbols.sort(key=lambda x: x[1], reverse=True)
        lines.extend(
            [
                "### Removed Symbols (top 15)",
                "",
                "| Symbol | Size |",
                "|--------|------|",
            ]
        )

        for symbol, size in removed_symbols[:15]:
            display_symbol = format_symbol_for_display(symbol)
            lines.append(f"| {display_symbol} | {format_bytes(size)} |")

        if len(removed_symbols) > 15:
            total_removed_size = sum(s[1] for s in removed_symbols)
            lines.append(
                f"| *{len(removed_symbols) - 15} more removed symbols...* | *Total: {format_bytes(total_removed_size)}* |"
            )
        lines.append("")

    lines.extend(["</details>", ""])

    return "\n".join(lines)


def create_detailed_breakdown_table(
    target_analysis: dict | None, pr_analysis: dict | None
) -> str:
    """Create a markdown table showing detailed memory breakdown by component.

    Args:
        target_analysis: Component memory breakdown for target branch
        pr_analysis: Component memory breakdown for PR branch

    Returns:
        Formatted markdown table
    """
    if not target_analysis or not pr_analysis:
        return ""

    # Combine all components from both analyses
    all_components = set(target_analysis.keys()) | set(pr_analysis.keys())

    # Filter to components that have changed (ignoring noise ≤2 bytes)
    changed_components = []
    for comp in all_components:
        target_mem = target_analysis.get(comp, {})
        pr_mem = pr_analysis.get(comp, {})

        target_flash = target_mem.get("flash_total", 0)
        pr_flash = pr_mem.get("flash_total", 0)

        # Only include if component has meaningful change (>2 bytes)
        delta = pr_flash - target_flash
        if abs(delta) > 2:
            changed_components.append((comp, target_flash, pr_flash, delta))

    if not changed_components:
        return ""

    # Sort by absolute delta (largest changes first)
    changed_components.sort(key=lambda x: abs(x[3]), reverse=True)

    # Build table - limit to top 20 changes
    lines = [
        "",
        "<details open>",
        "<summary>📊 Component Memory Breakdown</summary>",
        "",
        "| Component | Target Flash | PR Flash | Change |",
        "|-----------|--------------|----------|--------|",
    ]

    for comp, target_flash, pr_flash, delta in changed_components[:20]:
        target_str = format_bytes(target_flash)
        pr_str = format_bytes(pr_flash)
        change_str = format_change(target_flash, pr_flash)
        lines.append(f"| `{comp}` | {target_str} | {pr_str} | {change_str} |")

    if len(changed_components) > 20:
        lines.append(
            f"| ... | ... | ... | *({len(changed_components) - 20} more components not shown)* |"
        )

    lines.extend(["", "</details>", ""])

    return "\n".join(lines)


def create_comment_body(
    components: list[str],
    platform: str,
    target_ram: int,
    target_flash: int,
    pr_ram: int,
    pr_flash: int,
    target_analysis: dict | None = None,
    pr_analysis: dict | None = None,
    target_symbols: dict | None = None,
    pr_symbols: dict | None = None,
    target_cache_hit: bool = False,
) -> str:
    """Create the comment body with memory impact analysis.

    Args:
        components: List of component names (merged config)
        platform: Platform name
        target_ram: RAM usage in target branch
        target_flash: Flash usage in target branch
        pr_ram: RAM usage in PR branch
        pr_flash: Flash usage in PR branch
        target_analysis: Optional component breakdown for target branch
        pr_analysis: Optional component breakdown for PR branch
        target_symbols: Optional symbol map for target branch
        pr_symbols: Optional symbol map for PR branch
        target_cache_hit: Whether target branch analysis was loaded from cache

    Returns:
        Formatted comment body
    """
    ram_change = format_change(target_ram, pr_ram)
    flash_change = format_change(target_flash, pr_flash)

    # Use provided analysis data if available
    component_breakdown = ""
    symbol_changes = ""

    if target_analysis and pr_analysis:
        component_breakdown = create_detailed_breakdown_table(
            target_analysis, pr_analysis
        )

        if target_symbols and pr_symbols:
            symbol_changes = create_symbol_changes_table(target_symbols, pr_symbols)
    else:
        print("No ELF files provided, skipping detailed analysis", file=sys.stderr)

    # Format components list
    if len(components) == 1:
        components_str = f"`{components[0]}`"
        config_note = "a representative test configuration"
    else:
        components_str = ", ".join(f"`{c}`" for c in sorted(components))
        config_note = f"a merged configuration with {len(components)} components"

    # Add cache info note if target was cached
    cache_note = ""
    if target_cache_hit:
        cache_note = "\n\n> ⚡ Target branch analysis was loaded from cache (build skipped for faster CI)."

    return f"""{COMMENT_MARKER}
## Memory Impact Analysis

**Components:** {components_str}
**Platform:** `{platform}`

| Metric | Target Branch | This PR | Change |
|--------|--------------|---------|--------|
| **RAM** | {format_bytes(target_ram)} | {format_bytes(pr_ram)} | {ram_change} |
| **Flash** | {format_bytes(target_flash)} | {format_bytes(pr_flash)} | {flash_change} |
{component_breakdown}{symbol_changes}{cache_note}

---
> **Note:** This analysis measures **static RAM and Flash usage** only (compile-time allocation).
> **Dynamic memory (heap)** cannot be measured automatically.
> **⚠️ You must test this PR on a real device** to measure free heap and ensure no runtime memory issues.

*This analysis runs automatically when components change. Memory usage is measured from {config_note}.*
"""


def find_existing_comment(pr_number: str) -> str | None:
    """Find existing memory impact comment on the PR.

    Args:
        pr_number: PR number

    Returns:
        Comment numeric ID if found, None otherwise
    """
    try:
        print(
            f"DEBUG: Looking for existing comment on PR #{pr_number}", file=sys.stderr
        )

        # Use gh api to get comments directly - this returns the numeric id field
        result = subprocess.run(
            [
                "gh",
                "api",
                f"/repos/{{owner}}/{{repo}}/issues/{pr_number}/comments",
                "--jq",
                ".[] | {id, body}",
            ],
            capture_output=True,
            text=True,
            check=True,
        )

        print(
            f"DEBUG: gh api comments output (first 500 chars):\n{result.stdout[:500]}",
            file=sys.stderr,
        )

        # Parse comments and look for our marker
        comment_count = 0
        for line in result.stdout.strip().split("\n"):
            if not line:
                continue

            try:
                comment = json.loads(line)
                comment_count += 1
                comment_id = comment.get("id")
                print(
                    f"DEBUG: Checking comment {comment_count}: id={comment_id}",
                    file=sys.stderr,
                )

                body = comment.get("body", "")
                if COMMENT_MARKER in body:
                    print(
                        f"DEBUG: Found existing comment with id={comment_id}",
                        file=sys.stderr,
                    )
                    # Return the numeric id
                    return str(comment_id)
                print("DEBUG: Comment does not contain marker", file=sys.stderr)
            except json.JSONDecodeError as e:
                print(f"DEBUG: JSON decode error: {e}", file=sys.stderr)
                continue

        print(
            f"DEBUG: No existing comment found (checked {comment_count} comments)",
            file=sys.stderr,
        )
        return None

    except subprocess.CalledProcessError as e:
        print(f"Error finding existing comment: {e}", file=sys.stderr)
        if e.stderr:
            print(f"stderr: {e.stderr.decode()}", file=sys.stderr)
        return None


def post_or_update_comment(pr_number: str, comment_body: str) -> bool:
    """Post a new comment or update existing one.

    Args:
        pr_number: PR number
        comment_body: Comment body text

    Returns:
        True if successful, False otherwise
    """
    # Look for existing comment
    existing_comment_id = find_existing_comment(pr_number)

    try:
        if existing_comment_id and existing_comment_id != "None":
            # Update existing comment
            print(
                f"DEBUG: Updating existing comment {existing_comment_id}",
                file=sys.stderr,
            )
            result = subprocess.run(
                [
                    "gh",
                    "api",
                    f"/repos/{{owner}}/{{repo}}/issues/comments/{existing_comment_id}",
                    "-X",
                    "PATCH",
                    "-f",
                    f"body={comment_body}",
                ],
                check=True,
                capture_output=True,
                text=True,
            )
            print(f"DEBUG: Update response: {result.stdout}", file=sys.stderr)
        else:
            # Post new comment
            print(
                f"DEBUG: Posting new comment (existing_comment_id={existing_comment_id})",
                file=sys.stderr,
            )
            result = subprocess.run(
                ["gh", "pr", "comment", pr_number, "--body", comment_body],
                check=True,
                capture_output=True,
                text=True,
            )
            print(f"DEBUG: Post response: {result.stdout}", file=sys.stderr)

        print("Comment posted/updated successfully", file=sys.stderr)
        return True

    except subprocess.CalledProcessError as e:
        print(f"Error posting/updating comment: {e}", file=sys.stderr)
        if e.stderr:
            print(
                f"stderr: {e.stderr.decode() if isinstance(e.stderr, bytes) else e.stderr}",
                file=sys.stderr,
            )
        if e.stdout:
            print(
                f"stdout: {e.stdout.decode() if isinstance(e.stdout, bytes) else e.stdout}",
                file=sys.stderr,
            )
        return False


def main() -> int:
    """Main entry point."""
    parser = argparse.ArgumentParser(
        description="Post or update PR comment with memory impact analysis"
    )
    parser.add_argument("--pr-number", required=True, help="PR number")
    parser.add_argument(
        "--components",
        required=True,
        help='JSON array of component names (e.g., \'["api", "wifi"]\')',
    )
    parser.add_argument("--platform", required=True, help="Platform name")
    parser.add_argument(
        "--target-ram", type=int, required=True, help="Target branch RAM usage"
    )
    parser.add_argument(
        "--target-flash", type=int, required=True, help="Target branch flash usage"
    )
    parser.add_argument("--pr-ram", type=int, required=True, help="PR branch RAM usage")
    parser.add_argument(
        "--pr-flash", type=int, required=True, help="PR branch flash usage"
    )
    parser.add_argument(
        "--target-json",
        help="Optional path to target branch analysis JSON (for detailed analysis)",
    )
    parser.add_argument(
        "--pr-json",
        help="Optional path to PR branch analysis JSON (for detailed analysis)",
    )
    parser.add_argument(
        "--target-cache-hit",
        action="store_true",
        help="Indicates that target branch analysis was loaded from cache",
    )

    args = parser.parse_args()

    # Parse components from JSON
    try:
        components = json.loads(args.components)
        if not isinstance(components, list):
            print("Error: --components must be a JSON array", file=sys.stderr)
            sys.exit(1)
    except json.JSONDecodeError as e:
        print(f"Error parsing --components JSON: {e}", file=sys.stderr)
        sys.exit(1)

    # Load analysis JSON files
    target_analysis = None
    pr_analysis = None
    target_symbols = None
    pr_symbols = None

    if args.target_json:
        target_data = load_analysis_json(args.target_json)
        if target_data and target_data.get("detailed_analysis"):
            target_analysis = target_data["detailed_analysis"].get("components")
            target_symbols = target_data["detailed_analysis"].get("symbols")

    if args.pr_json:
        pr_data = load_analysis_json(args.pr_json)
        if pr_data and pr_data.get("detailed_analysis"):
            pr_analysis = pr_data["detailed_analysis"].get("components")
            pr_symbols = pr_data["detailed_analysis"].get("symbols")

    # Create comment body
    # Note: Memory totals (RAM/Flash) are summed across all builds if multiple were run.
    comment_body = create_comment_body(
        components=components,
        platform=args.platform,
        target_ram=args.target_ram,
        target_flash=args.target_flash,
        pr_ram=args.pr_ram,
        pr_flash=args.pr_flash,
        target_analysis=target_analysis,
        pr_analysis=pr_analysis,
        target_symbols=target_symbols,
        pr_symbols=pr_symbols,
        target_cache_hit=args.target_cache_hit,
    )

    # Post or update comment
    success = post_or_update_comment(args.pr_number, comment_body)

    return 0 if success else 1


if __name__ == "__main__":
    sys.exit(main())