feat: add knowledge base core api

backend/apps/knowledge/models.py

@@ -0,0 +1,120 @@
+from django.conf import settings
+from django.db import models
+
+
+class KnowledgeBase(models.Model):
+    name = models.CharField(max_length=160)
+    description = models.TextField(blank=True)
+    scope = models.CharField(max_length=120, blank=True)
+    enabled = models.BooleanField(default=True)
+    created_by = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        null=True,
+        blank=True,
+        on_delete=models.SET_NULL,
+    )
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        ordering = ["-updated_at"]
+
+    def __str__(self) -> str:
+        return self.name
+
+
+class KnowledgeDocument(models.Model):
+    knowledge_base = models.ForeignKey(
+        KnowledgeBase,
+        on_delete=models.CASCADE,
+        related_name="documents",
+    )
+    file_name = models.CharField(max_length=255)
+    file_type = models.CharField(max_length=80, blank=True)
+    storage_path = models.CharField(max_length=500, blank=True)
+    content_text = models.TextField(blank=True)
+    parse_status = models.CharField(max_length=40, default="pending")
+    parse_error = models.TextField(blank=True)
+    created_by = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        null=True,
+        blank=True,
+        on_delete=models.SET_NULL,
+    )
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        ordering = ["-created_at"]
+
+
+class KnowledgeItem(models.Model):
+    knowledge_base = models.ForeignKey(
+        KnowledgeBase,
+        on_delete=models.CASCADE,
+        related_name="items",
+    )
+    title = models.CharField(max_length=200)
+    problem = models.TextField()
+    applicable_scope = models.TextField(blank=True)
+    error_code = models.CharField(max_length=120, blank=True)
+    root_cause = models.TextField(blank=True)
+    troubleshooting_steps = models.TextField(blank=True)
+    solution = models.TextField()
+    risk_note = models.TextField(blank=True)
+    status = models.CharField(max_length=40, default="draft")
+    source_type = models.CharField(max_length=40, default="manual")
+    source_ticket_id = models.BigIntegerField(null=True, blank=True)
+    created_by = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        null=True,
+        blank=True,
+        on_delete=models.SET_NULL,
+        related_name="created_knowledge_items",
+    )
+    reviewed_by = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        null=True,
+        blank=True,
+        on_delete=models.SET_NULL,
+        related_name="reviewed_knowledge_items",
+    )
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        ordering = ["-updated_at"]
+
+
+class KnowledgeChunk(models.Model):
+    knowledge_base = models.ForeignKey(
+        KnowledgeBase,
+        on_delete=models.CASCADE,
+        related_name="chunks",
+    )
+    document = models.ForeignKey(
+        KnowledgeDocument,
+        null=True,
+        blank=True,
+        on_delete=models.CASCADE,
+        related_name="chunks",
+    )
+    item = models.ForeignKey(
+        KnowledgeItem,
+        null=True,
+        blank=True,
+        on_delete=models.CASCADE,
+        related_name="chunks",
+    )
+    chunk_index = models.PositiveIntegerField(default=0)
+    content = models.TextField()
+    embedding = models.JSONField(default=list, blank=True)
+    embedding_model = models.CharField(max_length=120, default="local-hash-v1")
+    metadata = models.JSONField(default=dict, blank=True)
+    created_at = models.DateTimeField(auto_now_add=True)
+
+    class Meta:
+        ordering = ["knowledge_base_id", "document_id", "item_id", "chunk_index"]
+        indexes = [
+            models.Index(fields=["knowledge_base", "chunk_index"]),
+        ]