"""Edit tools: str_replace and patch_apply."""

import subprocess
from pathlib import Path
from typing import Any

from pydantic import BaseModel, Field

from app.models.tool_call import ToolResult, ToolResultStatus
from app.tools.base import BaseTool
from app.utils.file_helpers import (
    FileSizeError,
    PathSecurityError,
    resolve_safe_path,
    safe_read_file,
    safe_write_file,
)

_PATCH_TIMEOUT = 30


class StrReplaceParams(BaseModel):
    """Parameters for the str_replace tool."""

    file_path: str = Field(description="Path to the file to edit (relative to workspace root)")
    old_str: str = Field(description="The exact string to find and replace (must be unique in file)")
    new_str: str = Field(description="The replacement string")


class StrReplaceTool(BaseTool):
    """Replace a unique string occurrence in a file."""

    name = "str_replace"
    description = (
        "Replace exactly one occurrence of old_str with new_str in a file. "
        "Fails if old_str is not found or appears more than once."
    )
    params_model = StrReplaceParams

    def execute(
        self, *, tool_call_id: str, file_path: str, old_str: str, new_str: str, **kwargs: Any
    ) -> ToolResult:
        fs_config = self.config.tools.filesystem

        # Read the file
        try:
            content = safe_read_file(
                file_path,
                self.workspace_root,
                max_size_bytes=fs_config.max_file_size_bytes,
                check_binary=fs_config.binary_detection,
            )
        except PathSecurityError as exc:
            return ToolResult(
                tool_call_id=tool_call_id,
                tool_name=self.name,
                status=ToolResultStatus.ERROR,
                error=str(exc),
            )
        except FileNotFoundError as exc:
            return ToolResult(
                tool_call_id=tool_call_id,
                tool_name=self.name,
                status=ToolResultStatus.ERROR,
                error=str(exc),
            )
        except FileSizeError as exc:
            return ToolResult(
                tool_call_id=tool_call_id,
                tool_name=self.name,
                status=ToolResultStatus.ERROR,
                error=str(exc),
            )

        # Count occurrences
        count = content.count(old_str)
        if count == 0:
            return ToolResult(
                tool_call_id=tool_call_id,
                tool_name=self.name,
                status=ToolResultStatus.ERROR,
                error=f"old_str not found in {file_path}",
            )
        if count > 1:
            return ToolResult(
                tool_call_id=tool_call_id,
                tool_name=self.name,
                status=ToolResultStatus.ERROR,
                error=f"old_str appears {count} times in {file_path} (must be unique)",
            )

        # Perform replacement and write back
        new_content = content.replace(old_str, new_str, 1)
        try:
            safe_write_file(
                file_path,
                new_content,
                self.workspace_root,
                max_size_bytes=fs_config.max_file_size_bytes,
            )
        except PathSecurityError as exc:
            return ToolResult(
                tool_call_id=tool_call_id,
                tool_name=self.name,
                status=ToolResultStatus.ERROR,
                error=str(exc),
            )
        except FileSizeError as exc:
            return ToolResult(
                tool_call_id=tool_call_id,
                tool_name=self.name,
                status=ToolResultStatus.ERROR,
                error=str(exc),
            )

        try:
            safe_path = resolve_safe_path(file_path, self.workspace_root)
            rel_path = safe_path.relative_to(self.workspace_root)
        except (PathSecurityError, ValueError):
            rel_path = Path(file_path)

        return ToolResult(
            tool_call_id=tool_call_id,
            tool_name=self.name,
            status=ToolResultStatus.SUCCESS,
            output=f"Replaced 1 occurrence in {rel_path}",
        )


class PatchApplyParams(BaseModel):
    """Parameters for the patch_apply tool."""

    file_path: str = Field(description="Path to the file to patch (relative to workspace root)")
    patch: str = Field(description="Unified diff format patch to apply")


class PatchApplyTool(BaseTool):
    """Apply a unified diff patch to a file."""

    name = "patch_apply"
    description = (
        "Apply a unified diff (patch) to a file. The patch must be in standard "
        "unified diff format."
    )
    params_model = PatchApplyParams

    def execute(self, *, tool_call_id: str, file_path: str, patch: str, **kwargs: Any) -> ToolResult:
        try:
            safe_path = resolve_safe_path(file_path, self.workspace_root)
        except PathSecurityError as exc:
            return ToolResult(
                tool_call_id=tool_call_id,
                tool_name=self.name,
                status=ToolResultStatus.ERROR,
                error=str(exc),
            )

        if not safe_path.exists():
            return ToolResult(
                tool_call_id=tool_call_id,
                tool_name=self.name,
                status=ToolResultStatus.ERROR,
                error=f"File not found: {safe_path}",
            )

        try:
            result = subprocess.run(
                ["patch", "--forward", "--no-backup-if-mismatch", str(safe_path)],
                input=patch,
                capture_output=True,
                text=True,
                timeout=_PATCH_TIMEOUT,
                cwd=self.workspace_root,
            )
        except subprocess.TimeoutExpired:
            return ToolResult(
                tool_call_id=tool_call_id,
                tool_name=self.name,
                status=ToolResultStatus.ERROR,
                error=f"Patch timed out after {_PATCH_TIMEOUT}s",
            )
        except FileNotFoundError:
            return ToolResult(
                tool_call_id=tool_call_id,
                tool_name=self.name,
                status=ToolResultStatus.ERROR,
                error="'patch' command not found on system",
            )

        if result.returncode != 0:
            return ToolResult(
                tool_call_id=tool_call_id,
                tool_name=self.name,
                status=ToolResultStatus.ERROR,
                error=f"Patch failed (exit {result.returncode}): {result.stderr or result.stdout}",
            )

        try:
            rel_path = safe_path.relative_to(self.workspace_root)
        except ValueError:
            rel_path = safe_path

        return ToolResult(
            tool_call_id=tool_call_id,
            tool_name=self.name,
            status=ToolResultStatus.SUCCESS,
            output=f"Patch applied to {rel_path}",
        )