package com.suno.android.common_data

import org.junit.Assert
import org.junit.Test

class PartialJsonExtractorTest {
    private val extractor = PartialJsonExtractor()

    @Test
    fun `given complete JSON when extracting message field then returns full message`() {
        val json = """{"message":"Hello World"}"""

        val result = extractor.extractField(partialJson = json, fieldName = "message")

        Assert.assertEquals("Hello World", result)
    }

    @Test
    fun `given incomplete JSON when extracting message field then returns partial message`() {
        val json = """{"message":"Hello"""

        val result = extractor.extractField(partialJson = json, fieldName = "message")

        Assert.assertEquals("Hello", result)
    }

    @Test
    fun `given streaming SSE arguments when extracting message then accumulates correctly`() {
        val fragments = listOf(
            """{"message":"Hey""",
            """! What""",
            """ kind""",
            """ of sound""",
        )

        val results = mutableListOf<String>()
        fragments.forEachIndexed { index, _ ->
            val accumulated = fragments.subList(0, index + 1).joinToString("")
            val result = extractor.extractField(partialJson = accumulated, fieldName = "message")
            result?.let { results.add(it) }
        }

        Assert.assertEquals(
            listOf("Hey", "Hey! What", "Hey! What kind", "Hey! What kind of sound"),
            results,
        )
    }

    @Test
    fun `given JSON with escaped quotes when extracting then handles escapes correctly`() {
        val json = """{"message":"He said \"Hello\""}"""

        val result = extractor.extractField(partialJson = json, fieldName = "message")

        Assert.assertEquals("He said \"Hello\"", result)
    }

    @Test
    fun `given JSON without message field when extracting then returns null`() {
        val json = """{"other":"value"}"""

        val result = extractor.extractField(partialJson = json, fieldName = "message")

        Assert.assertNull(result)
    }

    @Test
    fun `given nested JSON when extracting message field then returns correct value`() {
        val json = """{"choices":["Pop"],"message":"Hello"}"""

        val result = extractor.extractField(partialJson = json, fieldName = "message")

        Assert.assertEquals("Hello", result)
    }

    @Test
    fun `given JSON with newlines when extracting then preserves newlines`() {
        val json = """{"message":"Line 1\nLine 2"}"""

        val result = extractor.extractField(partialJson = json, fieldName = "message")

        Assert.assertEquals("Line 1\nLine 2", result)
    }

    @Test
    fun `given incomplete JSON with partial field when extracting then returns what exists`() {
        val json = """{"mess"""

        val result = extractor.extractField(partialJson = json, fieldName = "message")

        Assert.assertNull(result)
    }

    @Test
    fun `given JSON with message field at different positions when extracting then finds it`() {
        val json = """{"other":"value","message":"Test","more":"data"}"""

        val result = extractor.extractField(partialJson = json, fieldName = "message")

        Assert.assertEquals("Test", result)
    }
}