import pytest
from jinja2 import TemplateSyntaxError

from haystack.components.builders import DynamicPromptBuilder


class TestDynamicPromptBuilder:
    def test_initialization(self):
        runtime_variables = ["var1", "var2"]
        builder = DynamicPromptBuilder(runtime_variables)
        assert builder.runtime_variables == runtime_variables

        # regardless of the chat mode
        # we have inputs that contain: prompt_source, template_variables + runtime_variables
        expected_keys = set(runtime_variables + ["prompt_source", "template_variables"])
        assert set(builder.__canals_input__.keys()) == expected_keys

        # response is always prompt regardless of chat mode
        assert set(builder.__canals_output__.keys()) == {"prompt"}

        # prompt_source is a list of ChatMessage or a string
        assert builder.__canals_input__["prompt_source"].type == str

        # output is always prompt, but the type is different depending on the chat mode
        assert builder.__canals_output__["prompt"].type == str

    def test_processing_a_simple_template_with_provided_variables(self):
        runtime_variables = ["var1", "var2", "var3"]

        builder = DynamicPromptBuilder(runtime_variables)

        template = "Hello, {{ name }}!"
        template_variables = {"name": "John"}
        expected_result = {"prompt": "Hello, John!"}

        assert builder.run(template, template_variables) == expected_result

    def test_processing_a_simple_template_with_invalid_template(self):
        runtime_variables = ["var1", "var2", "var3"]
        builder = DynamicPromptBuilder(runtime_variables)

        template = "Hello, {{ name }!"
        template_variables = {"name": "John"}
        with pytest.raises(TemplateSyntaxError):
            builder.run(template, template_variables)

    def test_processing_a_simple_template_with_missing_variables(self):
        runtime_variables = ["var1", "var2", "var3"]
        builder = DynamicPromptBuilder(runtime_variables)

        with pytest.raises(ValueError):
            builder.run("Hello, {{ name }}!", {})

    def test_missing_template_variables(self):
        prompt_builder = DynamicPromptBuilder(runtime_variables=["documents"])

        # missing template variable city
        with pytest.raises(ValueError):
            prompt_builder._validate_template("Hello, I'm {{ name }}, and I live in {{ city }}.", {"name"})

        # missing template variable name
        with pytest.raises(ValueError):
            prompt_builder._validate_template("Hello, I'm {{ name }}, and I live in {{ city }}.", {"city"})

        # completely unknown template variable
        with pytest.raises(ValueError):
            prompt_builder._validate_template("Hello, I'm {{ name }}, and I live in {{ city }}.", {"age"})

    def test_provided_template_variables(self):
        prompt_builder = DynamicPromptBuilder(runtime_variables=["documents"])

        # both variables are provided
        prompt_builder._validate_template("Hello, I'm {{ name }}, and I live in {{ city }}.", {"name", "city"})

        # provided variables are a superset of the required variables
        prompt_builder._validate_template("Hello, I'm {{ name }}, and I live in {{ city }}.", {"name", "city", "age"})