"""Tests for hokusai.prompt — prompt resolution and placeholder substitution."""

from __future__ import annotations

from pathlib import Path

from hokusai.prompt import (
    extract_placeholder_files,
    resolve_prompt,
    substitute_placeholders,
)


class TestSubstitutePlaceholders:
    """Test placeholder substitution in prompt text."""

    def test_no_placeholders(self, project_dir: Path) -> None:
        assert substitute_placeholders("Hello world", project_dir) == "Hello world"

    def test_single_placeholder(self, project_dir: Path) -> None:
        _ = (project_dir / "name.txt").write_text("World")
        result = substitute_placeholders("Hello {name.txt}", project_dir)
        assert result == "Hello World"

    def test_multiple_placeholders(self, project_dir: Path) -> None:
        _ = (project_dir / "first.txt").write_text("Alice")
        _ = (project_dir / "last.txt").write_text("Smith")
        result = substitute_placeholders("Dear {first.txt} {last.txt}", project_dir)
        assert result == "Dear Alice Smith"

    def test_escaped_placeholder(self, project_dir: Path) -> None:
        _ = (project_dir / "name.txt").write_text("World")
        result = substitute_placeholders("Hello \\{name.txt}", project_dir)
        assert result == "Hello {name.txt}"

    def test_double_escaped_placeholder(self, project_dir: Path) -> None:
        _ = (project_dir / "name.txt").write_text("World")
        result = substitute_placeholders("Hello \\\\{name.txt}", project_dir)
        assert result == "Hello \\World"

    def test_triple_escaped_placeholder(self, project_dir: Path) -> None:
        _ = (project_dir / "name.txt").write_text("World")
        result = substitute_placeholders("Hello \\\\\\{name.txt}", project_dir)
        assert result == "Hello \\{name.txt}"

    def test_nine_backslashes_before_placeholder(self, project_dir: Path) -> None:
        """Nine backslashes (odd) → 4 literal backslashes + literal {file.txt}."""
        _ = (project_dir / "file.txt").write_text("content")
        # 9 backslashes before {file.txt}: odd → escaped, halve to 4
        result = substitute_placeholders(
            "\\\\\\\\\\\\\\\\\\" + "{file.txt}", project_dir
        )
        assert result == "\\\\\\\\{file.txt}"

    def test_placeholder_at_start(self, project_dir: Path) -> None:
        _ = (project_dir / "greeting.txt").write_text("Hi there")
        result = substitute_placeholders("{greeting.txt}!", project_dir)
        assert result == "Hi there!"

    def test_placeholder_with_multiline_content(self, project_dir: Path) -> None:
        _ = (project_dir / "block.txt").write_text("line1\nline2\nline3")
        result = substitute_placeholders("Start: {block.txt} :End", project_dir)
        assert result == "Start: line1\nline2\nline3 :End"


class TestExtractPlaceholderFiles:
    """Test extraction of placeholder filenames from prompts."""

    def test_no_placeholders(self) -> None:
        assert extract_placeholder_files("Hello world") == []

    def test_single_placeholder(self) -> None:
        assert extract_placeholder_files("Hello {name.txt}") == ["name.txt"]

    def test_multiple_placeholders(self) -> None:
        result = extract_placeholder_files("{a.txt} and {b.txt}")
        assert result == ["a.txt", "b.txt"]

    def test_escaped_placeholder_ignored(self) -> None:
        assert extract_placeholder_files("\\{name.txt}") == []

    def test_double_escaped_included(self) -> None:
        assert extract_placeholder_files("\\\\{name.txt}") == ["name.txt"]

    def test_triple_escaped_ignored(self) -> None:
        assert extract_placeholder_files("\\\\\\{name.txt}") == []


class TestResolvePrompt:
    """Test full prompt resolution (file loading + placeholder substitution)."""

    def test_inline_prompt_no_placeholders(self, project_dir: Path) -> None:
        assert resolve_prompt("Just a string", project_dir) == "Just a string"

    def test_file_prompt(self, project_dir: Path) -> None:
        _ = (project_dir / "prompt.txt").write_text("From file")
        result = resolve_prompt("prompt.txt", project_dir)
        assert result == "From file"

    def test_nonexistent_file_treated_as_inline(self, project_dir: Path) -> None:
        result = resolve_prompt("no_such_file.txt", project_dir)
        assert result == "no_such_file.txt"

    def test_inline_with_placeholder(self, project_dir: Path) -> None:
        _ = (project_dir / "style.txt").write_text("impressionist")
        result = resolve_prompt("Paint in {style.txt} style", project_dir)
        assert result == "Paint in impressionist style"

    def test_multiline_prompt_with_placeholder(self, project_dir: Path) -> None:
        _ = (project_dir / "detail.txt").write_text("vivid colours")
        result = resolve_prompt("First line\nWith {detail.txt}", project_dir)
        assert result == "First line\nWith vivid colours"

    def test_file_prompt_no_placeholder_processing(self, project_dir: Path) -> None:
        """When the prompt is a file path, the file is loaded verbatim."""
        _ = (project_dir / "prompt.txt").write_text("Literal {not_a_file.txt}")
        result = resolve_prompt("prompt.txt", project_dir)
        assert result == "Literal {not_a_file.txt}"